Friday, June 17, 2016

The Barton Springs segment of the Edwards Aquifer has reached levels that have not been seen in the past 24 years. With rainfall totals over the past 13 months being well above average and with continual flow in the major creeks and rivers, water is recharging the aquifer at high rates (see figure below). Aquifer conditions are determined by flow measurements from Barton Springs as well as the level of water in the Lovelady monitor well, located in South Austin.

At 4:00 pm on May 31, 2016, the water level in the Lovelady well rose above a previous peak level from April 25, 2003. This level of 536.2 ft msl (above mean sea level) was the second highest water level measured in the Lovelady well. The highest level ever measured in the well was on June 7, 1992 with a level of 546.1 ft. Lovelady water level as of June 17, 2016 is 539.6 ft. Drought conditions for the aquifer are considered to be when the water level drops below 478.4 ft.

Flow conditions at Barton Springs are similarly high. Flooding of Barton Springs pool, due to storm events, makes measurement of flow difficult. However, the current estimate of flow from Barton Springs was reported as 115 cfs (cubic feet per second) by USGS. Average flows from Barton Springs are 53 cfs. The District declares drought when Barton Springs flow drops below 38 cfs.

The aquifer was still in drought in November 2014 when, owing to El Nino conditions and high rainfall in September and November, water levels started rising. Other than a dry summer of 2015, water levels have continued to rise to where they are now. For the past 13 months, the District weather station has measured a total of 71.3 inches of rain compared to average rainfall of 38 inches. Rainfall at Camp Mabry for these 13 months has totalled 65.8 inches.

Onion Creek, which is a major contributor of recharge to the aquifer, has been flowing continuously since October 30, 2015. Sustained flow in the creeks will cause water levels to continue rising. With the recently reported end to El Nino, drier conditions might be what to expect in the near future. But, with the currently high aquifer levels, drought conditions for the aquifer are not likely to occur before the end of 2016.

Drought Rules

Either Barton Springs OR the Lovelady Well can trigger a drought declaration by the Board. However, BOTH Barton Springs AND the Lovelady Well must be above their respective drought trigger levels to exit a drought declaration.